Process for the manufacture of the sulfate, sulfite, and oxid directly from the sulfid of lead.



J. GITSHAM. PROCESS FOR THE MANUFACTURE OF THE SULFATE, SULFITE, ANDOXID DIRECTLY FROM THE SULFID 0F LEAD. APPLICATION FILED MAR.2I, I916.

Patented Oct. 17, 1916.

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J. GITSHAM. PROCESS FOR THE MANUFACTURE OF THE SULFATE, SULFITE, ANDOXID DIRECTLY FROM THE SULFID 0F LEAD.

APPLICATION FILED MAR 21,1916. 1 ,201 ,955. Patented Oct. 17, 1916.

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, SULFITE, AND 0) (ID DIRECTLY FROM THE SULFID OF LEAD APPLICATION FILEDMAR.2I, 1916.

Patented Oct. 17,1916;

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a .7 27206715???" 7a27ze6 Q52? hawz/ 5 W I @0 rzc g UNITED STATES PATENTOFFICE.

JAMES GITSHAM, OF LONDON, ENGLAND.

PROCESS FOR THE MANUFACTURE OF THE SULFATE, SULFITE, AND OXID DIRECTLYFROM THE SULFID 0F LEAD.

Specification of Letters Patent.

Patented Oct. 17, 1916.

Application filed March 21, 1916. Serial N 0. 85,664.

To all whom it may concern:

Be it known that I, JAMns GITSHAM, a subject of the King of GreatBritain, residing at London, England, have invented a new and usefulImprovement in Processes for the Manufacture of the Sulfate, Sulfite,and Oxid Directly from the Sulfid of Lead, of which the following is aspecification.

This invention relates to an improved process for the manufacture of thesulfate, Tulite and oxid directly from the sulfid of According to myinvention, the sulfid, e. g. in the form of ore, is introduced in asubdivided state into an electric furnace, preferably one in which theheating is effected by means of an electric arc, and is therein directlyvolatilized at a temperature not less than 5000 degrees F. and theresultant volatilized sulfidis subjected while in a heated condition tothe action of oxygen, the product of the reaction, which consists mainlyof lead sulfate, lead sulfite and a trace of lead oxid, in the form ofan impalpable powder, being then separated from the gaseous medium inwhich it is suspended. This powder is of a suitable consistency formixing directly with a drying oil in order to form a paint.

Since the primary material is sulfid ore taken substantially in the formin which it is obtained from the mine and suitably reduced in size, andsince the only reagent employed with such primary material isatmospheric air, no fluxes or the like being required, it will be seenthat the process is an extremely economical and simple one. Moreoversince the heat is generated by electrical means, the powdery product andconsequently the paint prepared therefrom can be obtained of a very purecolor. Such paint will consist almost entirely of compounds, 6. 9. leadsulfate and sulfite, of a non-poisonous nature, so that, assum' g sulfidores of a suitable degree of purity are available, a pure white pigmentcan be obtained GUI taining only a very small proportion of poisonousmatter, thus fulfilling the requirements of modern hygiene.

The oxidation of the volatilized sulfid may be advantageously effectedby the oxygen of atmospheric air supplied to the volatilized materialmainly after the latter has left the electric furnace but while it isstill at an elevated temperature. This may be effected by withdrawingthe volatilized material from the electric furnace through an educationflue or combustion chamber by means of a suitable exhausting device andthen introducing air into said flue or chamber in order to oxidize theheated volatilized material therein.

In order to prevent clogging of the furnace, and also to assist in thestarting in operation of the apparatus, a suitable amount of air isadmitted to the furnace itself, this air serving as a carrier for thevolatilized material and also supplying oxygen for initiating theoxidation of the sulfid into sulfate andsulfite of lead.

In each case the air supplied to the volatilized material may beadvantageously preheated, e. g. by heat withdrawn from the air or othergases in the apparatus beyond the point where the oxidation of thevolatilized material is complete.

The products of the oxidation are collected in an extended passage orpassages provided with battles and into'which the volatilized andoxidized material is delivered by the device whereby it is exhaustedfrom the electric furnace. The baflles near the outlet end of thecollecting passage may be advantageously sprayed with oil to enable thelast traces of powdery material to be removed from the gaseous medium(e. y air from which a large proportion of the oxygen has been removedby the oxidation) in which this product is suspended. This oil mayadvantageously consistof linseed or other drying oil suitable for use inthe preparation of a paint.

In the accompanying drawing I have shown how my said invention may beconveniently and advantageously carried into practlee.

In this drawing, Figure l is a diagrammatic side elevation of thecomplete plant. Figs-2 and 3 are vertical sections taken on planes atright angles to each other, and Fig. 4 is a horizontal section, showingthe electric furnace drawn to a larger scale. Figs. 5 and 6 arerespectively a horizontal and a vertical section showing the arrangementfor spraying with oil the baflies in the depositing passage. Fig.- 7 isa transverse section of the depositing passage illustrating amodification. Figs. 8 and 9 are, respectively, a side and a frontelevation of the exterior of the furnace showing details ofconstruction.

The electric furnace A comprises an outer casing of firebrick with aninner lining of magnesite bricks or other suitable fire-resistingmaterial. Across the bottom of the furnace there extends a cast ironplate B, which is covered with carbon slabs C, C, so as to form oneelectrode, 6. g. the negative electrode of the furnace. The otherelectrode, the positive electrode, consists of a carbon rod I) providedwith suitable controlling mechanism, whereby an arc maybe maintained inthe interior of the furnace A. For example, as shown in Figs. 8 and 9,the carbon rod-D can be mounted in a holder 4 slidable in suitableguides 5, 5 and counterbalanced by a weight 6 connected to such holderby a wire rope, extending over a pulley 8. The carbon rod can be fedforward into the furnace in any suitable manner, for example by means ofa rack 9 on said holder engaging a pinion 10 actuated through ahand-wheel 11, the rate of feed being preferably such as to maintain thecurrent at a constant value.

E is a suitable source of electric energy, here shown as a continuouscurrent dynamo.

E is the connection between the dynamo and the plate B.

' In the upper wall of the furnace, there is arranged a feed hopper F,in the delivery chute of which an Archimedean screw G is rotatablymounted and driven, e. g. through bevel and belt gearing H, J, so as toinsure that the sulfid ore or other sulfid shall be fed to the arc at auniform rate.

K is a tap-hole, through which the slag or other residue that is notvolatilized by the arc can be drawn 011'. When not in use, this tap-holeis closed by means of fire-clay.

M is an inlet controlled by a valve N for enabling air to be supplied tothe interior of the furnace, in order to oxidize the materialvolatilized by the arc. O is the outlet for the air, volatilizedmaterial and the products of the reaction between the oxygen of said airand the volatilized material. This outlet communicates with a flue Pwhich is also provided with an air-inlet Q, controlled by a damper orvalve R and is preferably formed of fire-brick or other suitablerefractory material, so that its interior is capable of being heated toa high temperature, e. y at the part near the furnace, where the burningor oxidation of the sulfid into sulfate and sulfite mainly takes place.The products of the reaction are drawn along the flue P by means of anexhausting fan S, whereby they are delivered into. the inlet end of adepositing passage T provided with baflies U, U. The outlet end of thepassage T is in communication with the bottom of a chimney stack V,whereby the contents of chain ,or the like 7 the flues P, T are carriedalong in the direction away from the furnace. In order to insure thatthe gases discharged into the atmosphere shall not carry with them anyof the powdery products of the reaction, oil is sprayed from the nozzlesW, W on to the baffles U, U, the last traces of dust contained in thegases being caught in the oil and retained for use.

An advantageous length of the flue P has been found to be about 150feet, the air-inlet Q, being arranged at from 8 to 25 feet from thefurnace. An advantageous length of the depositing passage T is 600 feet.These dimensions are, however, only given by way of example. I

' -The air for oxidizing the volatilized materials can be heated on itsway to the inlets M, Q by passing it through a conduit 1, which isformed of metal of good thermal conductivity and is arranged in thepassage T, see Fig. 7. This conduit is made with an inwardly turnedportion 2, in order to subject all the air therein to the heat from thegases outside. Moreover its outer surfaces are inclined as shown so asto prevent accumulation thereon of the powdery products of the reaction.suitable shape may however this purpose.

The operation is as follows :When dealing with lead sulfid ore, it isfed in a suitable state of subdivision, for example crushed to a finestate, into the arc in the furnace, and air is admitted at one or bothof the inlets M, Q. The lead sulfid in the ore will thereby beimmediately volatilized and subsequently oxidized by the oxygen of theair admitted, so as to form a mixture of sulfate, sulfite and oxid, theheat of combustion of the sulfur assisting in maintaining thetemperature necessary for the reaction. The powdery material formedgradually deposits itself in the flue P and passage T and is collectedand removed therefrom in any suitable known manner.

Since. the powdery material obtained as above described is of a suitableconsistency for the manufacture of paint, it can be readily convertedinto the same by grinding or mixing with linseed oil or other suitabledrying oil.

When starting operations, the major portion of the air is preferablyadmitted at the be employed for inlet M. When, however, the flue P hasbeen heated up to a temperature suitable for the oxidation of thevolatilized material, the supply of air through the inlet Q can be increased and that through the inlet M decreased.

I claim: I 1. A process of obtaining sulfate, sulfite and oxid directlyfrom the sulfid of lead,

said process consisting in introducing the sulfid in a subdivided stateinto an electric Air-conduits of any other furnace, directlyvolatilizing the same in such furnace, subjecting the resultantvolatilized material While in a heated condition to the action ofoxygen, and then separating the product of the reaction from the gaseousmedium in which it is suspended.

2. A process of treating lead sulfid ore, consisting in volatilizing inan electric furnace the ore which has been suitably reduced in size andoxidizing the volatilized mate- 10 ria thereby forming a mixture of leadsulfate, lead sulfite and lead oxid adapted for use as a color orpigment, substantially as described.

JAMES GITSHAM. Witnesses:

GEORGE HARRISON, CONRAD K. FAL RENSTEIN.

